1. Field of the Invention
The present invention relates to an electric motor which includes a casing member housing a stator core and to an electric vehicle.
2. Description of the Related Art
Electric motors have been known each of which includes a casing member housing a stator core, a coil and a rotor. In an electric motor, the polarity of a coil is repeatedly reversed, so that a rotor provided inside a stator core is rotated about an axle. Note that electric motors are used, for example, as power sources for electric vehicles.
Here, to improve heat dissipation performance for heat transferred from a coil provided to a stator core, a technique (hereinafter referred to as a first technique) has been proposed in which a resin is filled into a casing member, while a stator core is mounted in the casing member (for example, see Japanese Patent Application Publication No. 2007-60834).
Moreover, to improve the bonding strength between a stator core and a casing member, a technique (hereinafter referred to as a second technique) has been proposed in which, grooves are provided to a side surface which constitutes the outer periphery of a stator core, and a resin is filled into an opening (groove) formed between the stator core and the casing member (for example, see Japanese Patent Application Publication No. 2003-61278).
Here, stress is generated in the rotation direction of the rotor at interfaces of the casing member with contents (such as the stator core and the resin) housed in the casing member.
With the first technique described above, however, the force to prevent the contents housed in the casing member from rotating relies on the bonding strength between the resin and the casing member. In addition, with the second technique, the stator core is prevented from rotating by the resin filled into the grooves provided in the stator core, and the force to prevent the resin from rotating relies on the bonding strength between the resin and the casing member. As described above, in each of the first and second techniques, since the force to prevent the contents housed in the casing member from rotating relies on the bonding strength between the resin and the casing member, the contents housed in the casing member may rotate in same cases.
Moreover, with the first technique, the contents are covered with the casing member, although such a fact is not particularly mentioned in the second technique. For this reason, the heat dissipation performance of the stator core is inefficient.
In this connection, the present invention has been made to solve the problems described above, and an object of the present invention is to provide an electric motor capable of preventing contents housed in a casing member from rotating and an electric vehicle.
Another object of the present invention is to provide an electric motor and an electric vehicle capable of improving the heat dissipation performance of a stator core.